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Air-water heat pumps


Dipl.-Ing. R. Noack


Test according DIN EN 14511 and 14825

The ILK Dresden has an accredited testing laboratory and offers independent tests for the following certification bodies, organisations or quality labels:

  • EHPA Quality Label
  • CEN HP-Keymark certification
  • Tests according to ErP
  • Verification test of efficiency for state subsidies
    (e.g. BAFA, MCS, Harp)

Various types of air to water heat pumps are tested in the ILK test center - PLWP. Tests are carried out on

  • fix speed heat pumps
  • variable speed heat pumps
  • heat pumps with special design (direct condensing, with thermal storage, etc.)

Devices are tested in compact and split design for indoor or outdoor arrangement.

The Testzentrum PLWP is accredited to DIN EN ISO / IEC 17025 for the following performance and sound measurements

  • DIN EN 14511, DIN EN 14825 and DIN EN 16147
  • DIN EN 12102 and DIN EN 9614

Research and Development

We support the industry in its efforts to develop energy-efficient refrigeration systems and heat pumps.

The ILK Dresden has been active in the development and testing of refrigeration and heat pump technology for many years. The development work is carried out individually and in close cooperation with the client. The experiences of the ILK Dresden were and are continuously collected in a multiplicity of research projects.

In recent years, for example, the development of a high-temperature heat pump with operation temperatures above 120 °C has been an important research project.

Within the limits of our flexible accreditation, further measurement tasks can be carried out in accordance with applicable testing standards. Outside accreditation, further services can be offered:

  • Performance testing of WP with storage tanks
  • dynamic power measurements by means of temperature and power profile
  • Investigations of the cooling circuit of the heat pump
  • Expert opinions and evaluations of individual components
  • Characterisation of the operating behaviour of the heat pump
  • Refrigerant and material testing
  • Modifications of the systems by qualified refrigeration technicians on site in consultation with the customer

For measurements on (pre-) series devices as well as prototypes an additional air volume flow measurement is possible. A qualified measuring section with a max. air volume flow of approx. 5000 m³/h is available for this purpose. This results in extended evaluation possibilities for the current standard, which can be used for device optimization.

  • Source side balancing possible
  • Variation air volume
  • Simulation of real outdoor installation conditions

Short description of test procedure

The measurements of the heat pumps are carried out in accordance with currently valid guidelines (ErP) and standards DIN EN 14511 or DIN EN 14825. If required, minor deviations are possible due to our flexible accreditation (see below Annexes to accreditation, p. 3)

A multi-zone climate chamber is available for the tests. Measurements of small refrigeration capacities can be also carried out using the calorimeter method with environmental compensation in this climate chamber. The testing of the heating capacity is normally based on the water-enthalpy method. For this, the water mass flow and the temperatures are measured directly at the inlet and outlet of the heat pump. The test points are based on the current guidelines and test standards of certification bodies, quality labels (EHPA guidelines) and current standards.

Heat pumps with fixed-speed compressors and power-controlled heat pumps can be tested. Outside the accreditation of the Testzentrum PLWP, dynamic tests under changing conditions depending on the heat load are also possible. For this purpose, appropriate temperature and heat load profiles can be specified.

The performance data of the test rig are given in the following tables.

Performance data of the test rig

Heat source air

A multi-zone climate chamber is available to simulate the air side. Depending on the installation conditions, the heat pump is installed inside or outside the climate chamber. Split heat pumps are installed inside and outside the climate chamber.

Measured variable Unit min. range of application max. range of application
Heating capacitykW0,525
Refrigerating capacitykW115
Volume flowm³/h 5005000
Air temperature at inlet°C -2040
Humidity at inlet1)%rel.H ~20~100

1) max. humidification 10 kg/h

Heat sink water

A water circuit is used as a heat sink, which is adjusted to the test conditions via a mixing station and provides tempered water at the heat pump inlet. The water content of the water circuit used is sufficiently large to prevent thermal feedback.

Measured variable Unit min. range of application max. range of application
Water volume flowl/min580
Water temperature at inlet°C 570

Electrical power measurement

The electrical power consumption is measured with a precision power analyzer. The mains voltage in the test field is specially stabilised for power measurement.

Measured variable Unit min. range of application max. range of application
Power consumptionW 0,110 000
FrequencyHzsupply frequency (50)supply frequency (50)
VoltageV 1~/2303~/400

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